Conventionally, a process of jointing reinforcing bars imbedded in concrete of a reinforced concrete construction uses, for example, joints which are joined to each other by welding or the like. Another is a lap joint process utilizing metal wires which are wound around a lapped portion of ends of the reinforcing bars for jointing thereof.
A further another jointing process uses threaded joints, in which threads are provided in ends of reinforcing bars. A further another jointing process uses a mortar joint for jointing reinforcing bars to each other by a bond performance of a mortar which is filled to surround the reinforcing bars.
The conventional jointing process for jointing the reinforcing bars by welding requires a lot of time and efforts for welding the reinforcing bars to each other in a construction site, and a special welding technique is necessary for the welding, causing an inefficient working step. The lap jointing process in which a metal wire is wound around a lapped portion of opposed reinforcing bars requires a lot of time and efforts to wind the metal wire around the lapped portion. The screw joint having a threaded portion at a jointing end of a reinforcing bar also requires a lot of time and efforts for forming a thread on a reinforcing bar to join opposed steel bars to each other, causing an inefficient working step.
Furthermore, the mortar jointing process depends on a bonding strength between the reinforcing bar and the concrete to join a pair of opposed reinforcing bars to each other. Therefore, the reinforcing bars should have a lapping length to join each other. The mortar jointing process can not provide a sufficient bonding strength of the mortar for securing the reinforcing bars due to incorrect compounding ratios or mixing processes of composing materials. In the case of jointing reinforcing bars of concrete segmental products, end portions of the concrete segmental products are joined to each other, before the mortal of a securing material is supplied to the jointing portion of the concrete segmental products. Moreover, a worker can not see the mortal filled into the concrete segmental products to confirm a securing state thereof.
To eliminate the disadvantages of the conventional arts, the present invention provides an expansive filler joint and a reinforcing bar jointing process utilizing the expansive filler joint. The reinforcing bar jointing process allows efficient jointing of reinforcing bars without a lot of time and efforts and provides a sufficient bonding strength to firmly join the reinforcing bars with a shirt lapping length of the reinforcing bars. Furthermore, a filling state of the expanding agent can be easily seen in the case of jointing ends of concrete segmental products, and the expansive filler joint is simple in structure, allowing a low manufacturing and material cost.